根据下列句子及所给汉语注释，写出空缺处各单词的正确形式(每空只写一词)
【小题1】 These colorful (气球)make the garden more beautiful than usual.
【小题2】Customs officers examined all (行李) at the airport.
【小题3】You should think twice,but not jump at a (结论).
【小题4】 (非洲)is the second largest continent in the world.
【小题5】They like movies so they go to the (电影院) almost twice a week.
【小题6】On hearing the story,they burst into (笑声).
【小题7】He promised that he would be back on (星期四).
【小题8】They took (拥有) of the house as their own.
【小题9】He lay on his (胃) secretly to watch insects fighting.
【小题10】To tell you the (真相),I don’t agree with you.
在区间
单调增加，则满足
＜
的
取值范围是
时间内的图象均为半个周期的正弦曲线．求此交变电流的有效值． 
某地区为了解70-80岁的老人的日平均睡眠时间（单位：h），随机选择了50位老人进行调查，下表是这50位老人睡眠时间的频率分布表：